The present invention relates generally to communication systems, and more particularly to a method and apparatus for selection of a wireless communications network.
Mobile stations initiate Public Land Mobile Network (PLMN) discovery whenever they are powered on or move to a new registration area. The mobile station normally operates in its home PLMN (i.e., the PLMN normally associated with the subscriber""s service provider). The home PLMN is known by matching the mobile country code (MCC) and the mobile network code (MNC) of the home PLMN with the MCC and MNC of the International Mobile Station Identifier (IMSI). If the mobile station is unable to initiate contact with the home PLMN, it must look for and contact a different PLMN, also known as a visited PLMN. Often this occurs in roaming situations when the mobile station travels into areas not covered by its provider or home PLMN.
Once a suitable PLMN is discovered, the mobile station searches for a suitable cell of the chosen PLMN to provide cellular service. The mobile station then tunes to the control channel of the chosen cell and may register its presence in the registration area of the chosen cell. When the mobile station initiates a communication session (e.g., a phone call), the mobile station accesses the network on the control channel of the chosen cell. The mobile station sometimes continues to search for a more suitable cell within the PLMN at regular intervals, which may occur if the mobile station loses coverage of the chosen cell (e.g., the mobile station moves out of range).
Sometimes, a given area may have more than one PLMN (i.e., PLMN areas overlap), thereby requiring the mobile station to choose one PLMN over another when the mobile station is powered on. In other cases, the mobile station may lose coverage of a chosen PLMN and must select another network providing service, such as in roaming situations. The selection of a particular PLMN may be done either automatically or manually. Automatic selection uses a prioritized list of PLMNs, where the mobile station chooses the highest listed PLMN that is available. Manual selection offers a list of available PLMNs to the subscriber, and the subscriber must select the PLMN.
Currently, the list of available PLMNs and their priority is determined based on whatever network offers the strongest signal or strongest radio frequency (RF). For example, if a provider of a first PLMN offers a stronger signal than a provider of a second PLMN, then the mobile station will place the first PLMN higher on the list than the second PLMN. If the mobile station uses automatic selection, then the first PLMN would be chosen automatically based on its signal strength.
If using a visited PLMN, the mobile station may continue to periodically search for its home PLMN. A fuller explanation of current PLMN selection may be found in xe2x80x9cUniversal Mobile Telecommunications System (UMTS) Non-Access-Stratum functions related to Mobile Station (MS) in idle mode,xe2x80x9d 3GPP TS 23.122, v.4.1.0, Release 4, European Telecommunications Standards Institute (2001), and in xe2x80x9cUpper Layer (Layer 3) Signaling Standard for cdma2000 Spread Spectrum Systems,xe2x80x9d xc2xa72.6.1, pp. 2-33 to 2-43, TIA/EIA/IS-2000.5-A, Telecommunications Industry Association (March 2000).
With the deployment of third generation (3G) multimedia services, various PLMNs and providers will have different capabilities to cater to different needs of subscribers who require different types of communication services. For example, some high-end communication services (e.g., streaming video, Internet browsing, etc.), will require high bandwidth PLMNs, whereas more basic services (e.g., voice services, simple text messaging, etc.) may only require lower bandwidth PLMNs to communicate effectively. A particular service area may provide different communication services or different classes of service (e.g., different bandwidths, is guaranteed/nonguaranteed bandwidth, etc.) either on the same PLMN or among different PLMNs. For example, one PLMN may allow for both voice and video communication sessions each having different bandwidths requirements. Or one PLMN in an area may provide bandwidths dedicated to video services or other high-speed services, while another PLMN in the same area may provide bandwidths for only voice services or other basic services. The PLMN that is useful for video services may offer a communications bandwidth that is much greater than the communications bandwidth of the PLMN useful for voice services.
However, as mentioned above the current method of selecting a PLMN is based only on signal strength. Therefore, a mobile station that only needs a bandwidth for basic services may choose a PLMN that offers a high bandwidth if that PLMN offers the strongest signal. This results in inefficient use of bandwidth if the mobile station chooses that PLMN. Conversely, a mobile station that requires high bandwidth service may choose a PLMN that has a low bandwidth also because that PLMN offered the strongest signal. In this case, the mobile station cannot communicate effectively due to the bandwidth limitations of the PLMN.
Thus, there is a need for a method and apparatus that allows a mobile station to choose a PLMN that will meet the bandwidth needs of the mobile station while efficiently utilizing bandwidth resources.